$f(n)=64+6n$ Complete the recursive formula of $f(n)$. $f(1)=$
$f( 1)=64+6( 1)={70}$ $f( 2)=64+6( 2)={76}$ $f( 2)-f( 1)={76}-{70}={6}$ So the first term of the sequence is ${70}$ and the common difference is ${6}$. This is the recursive formula of the sequence: $\begin{cases} f(1)={70} \\\\ f(n)=f(n-1)+{6} \end{cases}$